The Federal Election Commission debated a proposal Thursday to let candidates and committees accept bitcoins as in-kind contributions, in the same way computer equipment or shares of stock are sometimes given as donations. The six-member panel appeared to be leaning toward sanctioning them, as long as it can resolve concerns about whether the Internet cash could be used to mask the identities of donors. “There’s a balancing act here,” Commissioner Matthew Petersen, a Republican appointee, said at the end of an hour-long discussion. “There’s this new technology that no one wants to strangle in its infancy,” but the panel also is “trying to make sure that there are adequate protections so that it couldn’t serve as a vehicle for illegal or prohibited contributions to flood into the system.” The FEC is one of the first federal agencies moving to issue guidance on the use of bi...